Improvement in adjustable bits



F. JONAS.

Adjustable Bits.

Patented April 1, 1873,

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AM. PHOTU-L/THOGRA PHIC ca N1 (enamel? moons} UNITED STATES PATENTQFFICE.

FREDRIOK JONAS, OF BURLINGTON, IOWA, ASSIGNOR OF ONE-HALF HIS RIGHT TOGEORGE O. BAY, OF SAME PLACE.

IMPROVEMENT IN ADJUSTABLE BITS.

Specification forming part of Letters Patent No. 137,373, dated April 1,1873 application filed August 17, 1872.

To all whom it may concern:

Be it known that I, FREDRICK JONAS, of

Burlington, county of Des Moines and Stateof Iowa, have invented certainImprovements in Adjustable Bits, of which the following is aspecification:

The nature of my invention relates to improvements in bits for boringholes for screwbolts, and at the same time cutting a countersink for thebolt-head and the inlaying plug. The invention consists in anew andimproved combination of devices, whereby the bit for drilling or boringthe hole for the bolt or screw and the bit for cutting the countersinkfor its head are secured on one stock by means of the same set-screw, insuch manner as to permit of their being adjusted independently of, orwith relation to, each other, as desired, all as hereinaftermorefullyset forth.

Description of the Accompanying Drawing.

Figure 1 is a side view of a bit and stock embodying my invention. Fig.2 is a longitudinal sectional view of Fig. 1 on the line a: a. Fig. 3 isa transverse sectional View of Fig. 1 on the line y 3;. Fig. 4 is an endview, and Fig. 5 is a view. of the stock alone.

General Description.

through one side of the collar D and one side of the tubular part of thestock A, its end resting against the giml'etB and securing it in place,at the same time securing the collar D in place and. drawing it towardthat side of the stock A. G is the countersinking-bit, having a flat,rectangular, oblongshaped shank, g, as shown at Figs. 2 and 3, carryingat its forward end the shearing-point and cutter of an ordinarycenter-bit, and its central forward part grooved out longitudinally forthe reception of the gimlet-bit B, as shown at Fig. 4. The shank of thebit G rests against the side of the stock A, which is flattened slightlyfor its better security, and being inside of the collar D, it will beevident that said collar may be made to hold it securely in place bymeans of the set-screw E.

The operation of my invention is as follows The hits B and G beingplaced in their respective seats, and the set-screw E turned back toallow them to be moved freely, they may then be adjusted as follows:First, the gimlet-bit B may be setwith its boring end the distance fromthe foot or guide 0 which it is desired to bore the hole in depth forthe reception of the screw-bolt shank; then the cutting end of the bit Gmay be set the dis tance from the foot G whichit is desired to bore indepth the countersink for the bolthead and the inlaying plug, and byturning the set-screw E both bits may be secured firmly in position, ashereinbefore described. The stock A may now be fixed in an ordinarybrace, and the operation of boring the holes for the screw-bolts andcountersinks rapidly performed at the same operation, the exact andrelative depth of each being under the control of the operatorby theadjustment of parts described, the foot 0 acting as a stop or guide forlimiting the depths bored by each bit. A bevel, 0, may be cut on theface of the flange 0 to allowthe escape of the shavings.

Claim.

.. FREDRIOK JONAS.

Witnesses:

J. J. TUNNICLIFF, M. H.- BAR-RINGER'.

